/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.core.namedparam;

import java.beans.PropertyDescriptor;
import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.BeanWrapper;
import org.springframework.beans.NotReadablePropertyException;
import org.springframework.beans.PropertyAccessor;
import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.jdbc.core.StatementCreatorUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;

/**
 * {@link SqlParameterSource} implementation that obtains parameter values
 * from bean properties of a given JavaBean object. The names of the bean
 * properties have to match the parameter names.
 *
 * <p>Uses a Spring BeanWrapper for bean property access underneath.
 *
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @see NamedParameterJdbcTemplate
 * @see org.springframework.beans.BeanWrapper
 * @since 2.0
 */
public class BeanPropertySqlParameterSource extends AbstractSqlParameterSource {

    private final BeanWrapper beanWrapper;

    @Nullable
    private String[] propertyNames;


    /**
     * Create a new BeanPropertySqlParameterSource for the given bean.
     *
     * @param object the bean instance to wrap
     */
    public BeanPropertySqlParameterSource(Object object) {
        this.beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(object);
    }


    @Override
    public boolean hasValue(String paramName) {
        return this.beanWrapper.isReadableProperty(paramName);
    }

    @Override
    @Nullable
    public Object getValue(String paramName) throws IllegalArgumentException {
        try {
            return this.beanWrapper.getPropertyValue(paramName);
        } catch (NotReadablePropertyException ex) {
            throw new IllegalArgumentException(ex.getMessage());
        }
    }

    /**
     * Derives a default SQL type from the corresponding property type.
     *
     * @see org.springframework.jdbc.core.StatementCreatorUtils#javaTypeToSqlParameterType
     */
    @Override
    public int getSqlType(String paramName) {
        int sqlType = super.getSqlType(paramName);
        if (sqlType != TYPE_UNKNOWN) {
            return sqlType;
        }
        Class<?> propType = this.beanWrapper.getPropertyType(paramName);
        return StatementCreatorUtils.javaTypeToSqlParameterType(propType);
    }

    @Override
    @Nullable
    public String[] getParameterNames() {
        return getReadablePropertyNames();
    }

    /**
     * Provide access to the property names of the wrapped bean.
     * Uses support provided in the {@link PropertyAccessor} interface.
     *
     * @return an array containing all the known property names
     */
    public String[] getReadablePropertyNames() {
        if (this.propertyNames == null) {
            List<String> names = new ArrayList<>();
            PropertyDescriptor[] props = this.beanWrapper.getPropertyDescriptors();
            for (PropertyDescriptor pd : props) {
                if (this.beanWrapper.isReadableProperty(pd.getName())) {
                    names.add(pd.getName());
                }
            }
            this.propertyNames = StringUtils.toStringArray(names);
        }
        return this.propertyNames;
    }

}
